Control method, controller, system and vehicle of distributed drive electric vehicle

Abstract

The present invention provides a control method, controller, system and vehicle for a distributed drive electric vehicle, comprising: determining a basic torque of each wheel according to an accelerator pedal opening and a vehicle fault level; determining an additional anti-skid torque and / or an additional yaw torque of the vehicle; adjusting each basic torque based on the additional anti-skid torque and / or the additional yaw torque, and outputting a required torque of each wheel; determining a drive control strategy according to the required torque of the wheel and the maximum output torque of each wheel hub motor; in this way, when the vehicle is integrated with a distributed drive system and a traditional chassis integrated control system at the same time, after determining the required torque of each wheel, a corresponding control strategy can be determined based on the maximum output torque of each wheel hub motor, and if the maximum output torque is insufficient, compensation is provided by the chassis integrated control system; thereby achieving overall coordination of the functional control of the distributed drive system and the chassis integrated control system, improving the utilization rate of control resources, and ensuring the control effect of the entire vehicle.

Description

Technical Field

[0001] The present application relates to the field of distributed drive vehicle control technology, and in particular to a control method, controller, system and vehicle for a distributed drive electric vehicle. Background Art

[0002] With the continuous deepening of electric vehicle technology research, the layout structure of the electric vehicle drive system has gradually developed from a centralized drive system with a single power source to a distributed drive system with multiple power sources.

[0003] However, when a distributed drive system and a traditional chassis integrated control system are integrated in a vehicle at the same time, the functions of the distributed drive system and the chassis integrated control system will overlap. For example, both the distributed drive system and the chassis integrated control system can realize longitudinal drive anti-skid and yaw stability control of the vehicle.

[0004] With a view to improving the vehicle's handling and driving stability, the existing technology is unable to coordinate the functional control of the distributed drive system and the chassis integrated control system, resulting in a waste of control resources and affecting the control effect of the entire vehicle. Summary of the invention

[0005] In response to the problems existing in the prior art, the embodiments of the present invention provide a control method, controller, system and vehicle for a distributed drive electric vehicle, so as to solve or partially solve the technical problem that the prior art cannot coordinate the functional control of the distributed drive system and the chassis integrated control system, resulting in a waste of control resources and also affecting the control effect of the entire vehicle.

[0006] A first aspect of the present invention provides a control method for a distributed drive electric vehicle, which is applied in a power chassis domain controller, and the method comprises:

[0007] Acquire the accelerator pedal opening and the vehicle fault level of the vehicle, and determine the basic torque of each wheel according to the accelerator pedal opening and the vehicle fault level;

[0008] determining an additional anti-slip torque of the wheel and / or an additional yaw torque of the vehicle;

[0009] adjusting each of the basic torques based on the additional anti-slip torque and / or the additional yaw torque, and outputting a required torque for each of the wheels;

[0010] The control strategy is determined according to the required torque of each wheel and the maximum output torque of each hub motor.

[0011] In the above solution, the basic torque of each wheel is determined according to the accelerator pedal opening and the vehicle fault level, including:

[0012] determining a first total basic torque of the vehicle according to the accelerator pedal opening;

[0013] Adjusting the first total basic torque based on the fault level to obtain a corresponding total required torque;

[0014] Allocating the total required torque into a front axle basic torque and a rear axle basic torque according to a torque distribution method;

[0015] The average value of the front axle basic torque is determined as the basic torque of the left front wheel and the right front wheel, and the average value of the rear axle basic torque is determined as the basic torque of the left rear wheel and the right rear wheel.

[0016] In the above solution, the determining of the additional anti-slip torque of the vehicle includes:

[0017] For any wheel, determining an actual slip rate of the wheel;

[0018] Based on the PID algorithm of the additional anti-slip torque, the actual slip rate of the wheel and the ideal slip rate of the wheel are determined as input values ​​of the additional anti-slip torque PID algorithm, and a first output value is obtained accordingly; the first output value is the additional anti-slip torque.

[0019] In the above solution, the determining the additional yaw torque of the vehicle includes:

[0020] When it is determined that the steering wheel angle of the vehicle is not 0, acquiring an actual yaw angular velocity of the vehicle;

[0021] determining an angular velocity difference between the actual yaw velocity and the ideal yaw velocity;

[0022] Based on the PID control algorithm of the additional yaw torque, the angular velocity difference is used as an input value of the additional yaw torque PID control algorithm, and a second output value is obtained accordingly; the second output value is the additional yaw torque of the vehicle.

[0023] In the above solution, the adjusting of each basic torque based on the additional anti-slip torque and / or the additional yaw torque and outputting the required torque of each wheel includes:

[0024] For any wheel, determining a torque adjustment amount according to the additional anti-slip torque and / or the additional yaw torque;

[0025] The basic torque is adjusted according to the torque adjustment amount to obtain the required torque of the corresponding wheel; wherein,

[0026] The required torque of the wheel is a torque sum of a basic torque required by the wheel and the torque adjustment amount.

[0027] In the above scheme, the driving control strategy is determined according to the required torque of each wheel and the maximum output torque of each hub motor, including:

[0028] For any wheel, if the maximum output torque of the hub motor is greater than or equal to the required torque of the corresponding wheel, the control strategy is determined as: the hub motor provides the required torque of the wheel.

[0029] In the above scheme, the driving control strategy is determined according to the required torque of each wheel and the maximum output torque of each hub motor, including:

[0030] If the maximum output torque of the hub motor is less than the required torque of the corresponding wheel, the control strategy is determined as: controlling the hub motor to output the maximum torque and compensating the target braking torque through the hydraulic circuit; the target braking torque is the difference between the required torque of the wheel and the maximum output torque of the hub motor.

[0031] A second aspect of the present invention provides a power chassis domain controller, the power chassis domain controller comprising:

[0032] Driving intention analysis module, used to obtain the vehicle's accelerator pedal opening;

[0033] A torque distribution module, used to determine the basic torque of each wheel according to the accelerator pedal opening;

[0034] a motor driven anti-skid control module, for determining an additional anti-skid torque for the wheel;

[0035] a motor torque vectoring control module for determining an additional yaw torque of the vehicle;

[0036] The drive arbitration module is used to adjust each of the basic torques based on the additional anti-slip torque and / or the additional yaw torque, and output the required torque of each wheel; and determine the control strategy according to the required torque of each wheel and the maximum output torque of each hub motor.

[0037] A third aspect of the present invention provides a control system for a distributed drive electric vehicle, the system comprising:

[0038] The vehicle controller VCU is used to obtain the vehicle fault level;

[0039] The power chassis domain controller of the second aspect is used to receive the fault level sent by the VCU, and determine the basic torque of each wheel based on the accelerator pedal opening of the vehicle and the vehicle fault level;

[0040] Determine the additional anti-slip torque of the wheel and / or the additional yaw torque of the vehicle; adjust each of the basic torques based on the additional anti-slip torque and / or the additional yaw torque, and output the required torque of each wheel; determine the control strategy according to the required torque required by each wheel and the maximum output torque of each hub motor.

[0041] A fourth aspect of the present invention provides a vehicle, wherein the vehicle comprises the control system of the distributed drive electric vehicle as described in the fourth aspect.

[0042] The present invention provides a control method, controller, system and vehicle for a distributed drive electric vehicle, the method comprising: obtaining the accelerator pedal opening and the vehicle fault level of the vehicle, determining the basic torque of each wheel according to the accelerator pedal opening and the vehicle fault level; determining the additional anti-skid torque of the vehicle and / or the additional yaw torque of the vehicle; adjusting each of the basic torques based on the additional anti-skid torque and / or the additional yaw torque, and outputting the required torque of each wheel; determining a drive control strategy according to the required torque required for each wheel and the maximum output torque of each hub motor; in this way, when the vehicle is integrated with a distributed drive system and a traditional chassis integrated control system at the same time, after determining the required torque of each wheel, the corresponding control strategy can be determined based on the maximum output torque of each hub motor, and if the maximum output torque is insufficient, the chassis integrated control system provides compensation; thereby achieving overall coordination of the functional control of the distributed drive system and the chassis integrated control system, improving the utilization rate of the control resources of the whole vehicle, and ensuring the control effect of the whole vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not considered to be limitations of the present invention. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings.

[0044] In the attached picture:

[0045] Figure 1 A schematic diagram of the overall structure of a control system of a distributed drive electric vehicle according to an embodiment of the present invention is shown;

[0046] Figure 2 A control logic diagram of a distributed drive electric vehicle according to an embodiment of the present invention is shown;

[0047] Figure 3 A schematic diagram of a control method for a distributed drive electric vehicle according to an embodiment of the present invention is shown;

[0048] Figure 4A schematic diagram of the structure of a power chassis domain controller according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0049] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0050] In order to better understand the technical solution of this application, the distributed drive system is first introduced here. The distributed drive electric vehicle is driven by two or more motors to drive their own wheels respectively, and the motor drives the wheels to move by controlling the torque and speed. Since the distributed drive system cancels the torque transmission of the intermediate differential, it has outstanding advantages such as short drive transmission chain, high transmission efficiency, and compact structure.

[0051] Electric vehicles equipped with distributed drive have the characteristics of four-wheel independent control. Pure electric vehicles can use the characteristics of four-wheel independent drive control to achieve refined tire adhesion distribution and improve vehicle handling and driving stability. Distributed drive systems can also match the optimal efficiency range of the motor with the working conditions of the vehicle to improve driving efficiency and energy utilization.

[0052] However, when a distributed drive electric vehicle approaches an unstable state while driving on the road, both the distributed drive system and the chassis integrated control system can effectively control the vehicle state, which leads to overlapping functions of the distributed drive system and the chassis integrated control system.

[0053] In addition, traditional chassis integrated control systems generally improve vehicle stability by reducing engine torque or independently controlling the braking force acting on the wheels. This control method requires reducing vehicle speed, which not only reduces the vehicle's driving ability, but also gives the driver a clear sense of intervention, causing driving interference to the driver.

[0054] Based on this, the embodiment of the present invention provides a control system for a distributed drive electric vehicle, such as Figure 1 As shown, the system includes: a vehicle control unit (VCU), a power chassis domain controller (CDU), an integrated electronic brake control system (IBC), and four wheel hub motors; among them,

[0055] The vehicle controller VCU is used to determine the vehicle fault level;

[0056] A power chassis domain controller CDU, configured to receive the fault level sent by the VCU, and determine the basic torque of each wheel based on the accelerator pedal opening of the vehicle and the fault level of the vehicle;

[0057] determining an additional anti-slip torque of the wheel and / or an additional yaw torque of the vehicle;

[0058] The basic torques are adjusted based on the additional anti-slip torque and / or the additional yaw torque, and the required torque of each wheel is output; and the control strategy is determined according to the required torque of each wheel and the maximum output torque of each hub motor.

[0059] IBC is used to control the output of each hydraulic circuit to the corresponding target braking torque based on the control strategy, and to recover braking energy according to the brake pedal opening.

[0060] Specifically, please refer to Figure 2 The power chassis domain controller CDU includes: a driving intention analysis module 21, a torque distribution module 22, a vehicle state determination module 23, a motor drive anti-skid control module (ETC, Electric Traction Control), a brake drive anti-skid control module (BTC, Brake Traction Control), a motor torque vector control module (TVC, Torque Vector Control), a brake stability control module (VDC, Vehicle Dynamics Control), a drive arbitration module 24 and a brake arbitration module 25.

[0061] The overall control logic of the control system of distributed drive electric vehicles is as follows:

[0062] Generally speaking, if the vehicle is in a good driving condition without slipping or instability, the CDU can drive directly according to the basic torque of the wheel without adjusting the basic torque of each wheel; at this time, the basic torque is a positive value.

[0063] If the vehicle starts at full throttle on a road with low adhesion coefficient (such as ice) or drives from a road with high adhesion coefficient to a road with low adhesion coefficient, a certain amount of additional anti-skid torque needs to be provided to improve the adhesion of the wheels and prevent the vehicle from skidding. Similarly, if the vehicle becomes unstable, a certain amount of additional yaw torque needs to be provided to improve the stability of the vehicle. In this case, the base torque should be a negative value.

[0064] Based on this, after the basic torque of each wheel is determined, the basic torque needs to be adjusted according to the additional anti-slip torque and / or the additional yaw torque to obtain the required torque of each wheel.

[0065] The vehicle control strategy is then determined based on the required torque of each wheel and the maximum output torque of the hub motor.

[0066] Specifically, first, the VCU will monitor the fault status of various vehicle components (such as IBC, power chassis domain controller and each wheel hub motor) in real time, and determine the vehicle fault level based on the fault status.

[0067] Then, the driving intention analysis module 21 analyzes the driving intention, obtains the corresponding accelerator pedal opening, and sends the accelerator pedal opening to the torque distribution module 22 .

[0068] The torque distribution module 22 distributes torque to each wheel according to the accelerator pedal opening and the vehicle fault level, determines the basic torque of each wheel, and sends the basic torque of each wheel to the driving arbitration module 24.

[0069] Then the vehicle state determination module 23 obtains the current driving parameters of the vehicle and determines the current vehicle state according to the current driving parameters, wherein the current driving parameters may include: steering wheel angle, vehicle speed, wheel speed and other information.

[0070] The vehicle state may include a slipping state and an unstable state, but the vehicle may only be in a slipping state, or only be in an unstable state, or both slipping and instability may exist at a given moment.

[0071] Therefore, if the vehicle state determination module 23 determines that the vehicle is currently in a slipping state, the ETC module will determine the additional anti-slip torque required by the wheels and send the additional anti-slip torque to the drive arbitration module 24 .

[0072] If it is determined that the vehicle is currently in an unstable state, the TVC module will determine the additional yaw torque required by the wheels and send the additional yaw torque to the drive arbitration module 24 .

[0073] If the vehicle is currently in both a slipping state and an unstable state, the ETC module sends an additional anti-slip torque to the drive arbitration module 24 , and the TVC module also sends an additional yaw torque to the drive arbitration module 24 .

[0074] After receiving the additional anti-slip torque and / or the additional yaw torque, the drive arbitration module 24 adjusts each basic torque based on the additional anti-slip torque and / or the additional yaw torque, and outputs the required torque of each wheel; then, drive arbitration is performed according to the required torque of each wheel and the maximum output torque of each hub motor to determine the corresponding control strategy.

[0075] For example, if the maximum output torque of the hub motor is greater than or equal to the required torque of the corresponding wheel, the control strategy is: the hub motor provides the required torque of the wheel; then the drive arbitration module 24 will send the required torque of each wheel to the corresponding hub motor for execution.

[0076] For example, assuming that the vehicle is in a slipping and unstable state at the same time, take the left front wheel as an example:

[0077] Assuming that the basic torque of the left front wheel is 30 N.m, the additional anti-slip torque is -50 N.m, and the additional yaw torque is -50 N.m, the required torque of the left front wheel is: 30-50-50=-70 N.m.

[0078] That is, the left front wheel requires 70N.m of braking torque to prevent the vehicle from skidding and becoming unstable.

[0079] If the maximum output torque of the left front wheel hub motor is -80N.m, the required torque of the left front wheel will be provided by the hub motor.

[0080] However, when the maximum output torque of the hub motor is less than the corresponding required torque and the vehicle is currently in a slipping state, the hub motor is given priority to provide the maximum output torque, and the remaining insufficient torque is determined as the first residual braking torque, and the BTC module sends the first residual braking torque to the braking arbitration module 25.

[0081] If the maximum output torque of the hub motor is less than the corresponding required torque and the vehicle is currently in an unstable state, the hub motor will be given priority to provide the maximum output torque, and the remaining insufficient torque will be determined as the second residual braking torque, and the VDC module will send the second residual braking torque to the braking arbitration module 25.

[0082] If the vehicle is currently in both a slipping state and an unstable state, the BTC module will send the first residual braking torque to the brake arbitration module 25 , and the VDC module will also send the second residual braking torque to the brake arbitration module 25 .

[0083] The brake arbitration module 25 determines a final target brake torque according to the first residual brake torque and / or the second residual brake torque.

[0084] It can be understood that if the vehicle is currently in a slipping state, the target braking torque is the first residual braking torque. If the vehicle is currently in an unstable state, the target braking torque is the second residual braking torque. If the vehicle is currently in a slipping state and in an unstable state at the same time, the target braking torque is the torque sum of the first residual braking torque and the second residual braking torque. The sum of the first residual braking torque and the second residual braking torque can also be understood as the difference between the required torque and the maximum output torque of the hub motor.

[0085] Then the corresponding control strategy is: control the wheel hub motor to output the maximum torque, and compensate the target braking torque through the braking hydraulic circuit.

[0086] The brake hydraulic circuit is controlled by the IBC, that is, after the brake arbitration module 25 determines the corresponding target braking torque, it will send a torque request to the IBC. After receiving the torque request, the IBC provides corresponding braking force to the wheels based on the target braking torque to suppress the vehicle from slipping and / or instability.

[0087] Continuing with the above example, assume that the vehicle is in a slipping and unstable state at the same time, and take the left front wheel as an example:

[0088] Assuming that the basic torque of the left front wheel is 30 N.m, the additional anti-slip torque is -50 N.m, and the additional yaw torque is -50 N.m, the required torque of the left front wheel is: 30-50-50=-70 N.m.

[0089] That is, the left front wheel requires 70N.m of braking torque to prevent the vehicle from skidding and becoming unstable.

[0090] If the maximum output torque of the left front wheel hub motor is -60N.m and the target braking torque is -10N.m, the CDU will send a torque request to the IBC, and the IBC will control the corresponding brake hydraulic pipeline to provide a target braking torque compensation of 10N.m.

[0091] In this way, this embodiment can coordinate and allocate the torque provided by the distributed drive system and the braking torque provided by the chassis integrated control system based on the vehicle status, solve the functional overlap problem of the distributed drive and chassis integrated control, realize the unified control of the distributed drive system and the chassis integrated control system, improve the utilization rate of control resources, and ensure the control effect of the whole vehicle.

[0092] Here, the specific execution logic of the power chassis domain controller CDU can refer to the specific description in the subsequent embodiments on the power chassis domain controller side, so it will not be repeated here.

[0093] Based on the same inventive concept as the above embodiment, this embodiment also provides a control method for a distributed drive electric vehicle, which is applied in a power chassis domain controller CDU, such as Figure 3 As shown, the method includes:

[0094] Step S310, obtaining the accelerator pedal opening and the vehicle fault level of the vehicle, and determining the basic torque of each wheel according to the accelerator pedal opening and the vehicle fault level;

[0095] As mentioned above, the VCU monitors the fault status of various vehicle components (such as IBC, power chassis domain controller and each wheel hub motor) in real time, determines the vehicle fault level according to the fault status, and sends the vehicle fault level to the CDU.

[0096] For example, if all components inside the vehicle are fault-free, the vehicle fault level is 0; if there is a component inside the vehicle with a level 1 fault, and the fault levels of all components do not exceed level 1, the vehicle fault level is 1; if there is a component inside the vehicle with a level 2 fault, and the fault levels of all components do not exceed level 21, the vehicle fault level is 2; if there is a component inside the vehicle with a level 3 fault, the vehicle fault level is level 3.

[0097] The CDU can collect the vehicle's accelerator pedal opening in real time, and receive the vehicle fault level sent by the VCU, and determine the basic torque of each wheel based on the accelerator pedal opening and the vehicle fault level.

[0098] In one implementation, determining the base torque of each wheel according to the accelerator pedal opening and the vehicle fault level includes:

[0099] determining a first total basic torque of the vehicle according to the accelerator pedal opening;

[0100] Adjusting the first total basic torque based on the fault level to obtain a corresponding total required torque;

[0101] Allocate the total required torque into a front axle basic torque and a rear axle basic torque according to a torque distribution method;

[0102] The average value of the front axle basic torque is determined as the basic torque of the left front wheel and the right front wheel, and the average value of the rear axle basic torque is determined as the basic torque of the left rear wheel and the right rear wheel.

[0103] Specifically, the first total basic torque expected by the vehicle is calculated based on the accelerator pedal opening and the vehicle state information. The vehicle state information includes: the maximum output current I currently allowed by the system A , the current speed of each hub motor and the current I corresponding to the peak torque of each hub motor a .

[0104] First, for each wheel hub motor, according to the current speed, query the motor speed-torque external characteristic table to obtain the corresponding maximum torque T tmaxi (i=1,2,3,4), i is the number of the hub motor. Then the total output torque T of the system can be determined by table lookup outmax for:

[0105] T outmax =T tmax1 +T tmax2 +T tmax3 +Ttmax4 ;in,

[0106] T tmax1 is the maximum torque of the first hub motor, T tmax2 is the maximum torque of the second wheel hub motor, T tmax3 is the maximum torque of the third wheel hub motor, T tmax4 This is the maximum torque from the table for the 4th wheel hub motor.

[0107] Then judge Is it greater than 1? If yes, If it is greater than or equal to 1, then it is determined that:

[0108] T outmax ′=T outmax ; Among them, T outmax ' is the maximum output torque allowed by the system.

[0109] If confirmed If it is less than 1, then it is confirmed

[0110] According to the formula T outmax ″=min(T outmax ,T outmax ′) Determine the final torque T outmax ″;

[0111] Finally, according to the formula T out =T outmax *Accpedal determines the first total base torque T out ; Among them, Accpedal is the accelerator pedal opening.

[0112] However, if a vehicle fails, the first total basic torque needs to be adjusted according to the corresponding fault level. In practical applications, the fault level and the torque adjustment coefficient have a corresponding relationship.

[0113] The above vehicle fault levels include 4 levels (0 to 3), and the torque adjustment coefficient also includes 4 levels correspondingly, which are 100%, 100%, 10%, and 0%, respectively.

[0114] For example, when the fault level is 0, the system operates normally and the first total basic torque does not need to be adjusted; when the fault level is 1, the system issues an alarm, but the first total basic torque continues to operate normally and does not need to be adjusted; when the fault level is 2, the first total basic torque is reduced to 0.1 times the normal torque; when the system fault level is 3, the system does not output torque and the torque is 0.

[0115] For example, assuming that the first total basic torque is 1000 N.m, the fault level is level 2, and the corresponding torque adjustment coefficient is 10% (0.1), then after adjusting the first total basic torque, the total required torque obtained is:

[0116] 1000*10%=100N.m.

[0117] After the total required torque is determined, the front and rear axle torque distribution ratio is determined based on the axle loads of the front and rear axles of the vehicle by adopting a torque distribution method proportional to the axle load, and then the front axle torque and rear axle torque are determined based on the front and rear axle torque distribution ratio.

[0118] For example, if the front and rear axle load ratio of the vehicle is 4:6, then the front and rear axle torque distribution ratio is also 4:6.

[0119] Then, the average value of the front axle basic torque is determined as the basic torque of the left front wheel and the right front wheel, and the average value of the rear axle basic torque is determined as the basic torque of the left rear wheel and the right rear wheel.

[0120] For example, assuming the total required torque is 800N.m and the front and rear axle torque distribution ratio is 4:6, then the front axle torque is 320N.m, the rear axle torque is 480N.m, the basic torque of the left front wheel and the right front wheel are 160N.m respectively, and the basic torque of the left rear wheel and the right rear wheel are 240N.m.

[0121] Step S311, determining an additional anti-slip torque of the wheel and / or an additional yaw torque of the vehicle;

[0122] As mentioned above, if the vehicle is in a good driving state without slipping or instability, the CDU can drive directly according to the basic torque of the wheel without adjusting the basic torque of each wheel. At this time, there is no need to suppress slipping and instability, so the basic torque is positive torque.

[0123] However, if the vehicle has been driving on a road with a low adhesion coefficient (such as ice) or is driving from a road with a high adhesion coefficient to a road with a low adhesion coefficient, a certain amount of additional anti-skid torque needs to be provided to increase the adhesion of the wheels and prevent the vehicle from skidding.

[0124] Similarly, if the vehicle becomes unstable, a certain amount of additional yaw torque will need to be provided to improve the stability of the vehicle.

[0125] Therefore, this embodiment also needs to determine the additional anti-slip torque of the wheel and / or the additional yaw torque of the vehicle.

[0126] In one embodiment, determining the additional anti-slip torque of the vehicle includes:

[0127] For any wheel, determine the actual slip rate of the wheel;

[0128] Based on the PID algorithm of the additional anti-slip torque, the actual slip rate of the wheel and the ideal slip rate of the wheel are determined as input values ​​of the additional anti-slip torque PID algorithm, and a first output value is obtained accordingly; the first output value is the additional anti-slip torque.

[0129] Specifically, the actual slip rate S of each wheel can be determined according to formula (1): x :

[0130]

[0131] In formula (1), x is the wheel number, r is the wheel rolling radius, ω is the wheel speed, and v is the current speed of the vehicle.

[0132] Then, the actual slip rate of the wheel and the ideal slip rate of the wheel are determined as the input values ​​of the additional anti-slip torque PID algorithm, and the first output value is obtained accordingly, and the first output value is the additional anti-slip torque T. The additional anti-slip torque PID algorithm is shown in formula (2):

[0133]

[0134] In formula (2), K p , K i and K d It is a pre-calibrated proportional coefficient, which is determined based on experience and the actual situation of the vehicle and is not limited here. e(t) input value, that is, e(t) is the actual slip rate of the wheel and the ideal slip rate of the wheel.

[0135] In one embodiment, determining an additional yaw torque of the vehicle includes:

[0136] When it is determined that the steering wheel angle of the vehicle is not 0, obtaining the actual yaw angular velocity of the vehicle;

[0137] determining an angular velocity difference between an actual yaw velocity and a desired yaw velocity;

[0138] Based on the PID control algorithm of the additional yaw torque, the angular velocity difference is used as the input value of the additional yaw torque PID control algorithm, and a second output value is obtained accordingly; the second output value is the additional yaw torque of the vehicle.

[0139] Specifically, when the steering wheel angle is not 0, the ideal yaw velocity of the vehicle can be determined using a two-degree-of-freedom vehicle reference model, the actual yaw velocity of the vehicle can be determined using a gyroscope, and then the difference between the ideal yaw velocity and the actual yaw velocity can be determined to obtain the corresponding angular velocity difference.

[0140] The angular velocity difference is used as the input value of the additional yaw torque PID control algorithm, and the output value is the additional yaw torque ΔM required to suppress vehicle instability. z It should be noted that the additional yaw torque of each wheel may be different. The additional yaw torque of each wheel is determined as follows:

[0141] Since the additional yaw torque is achieved by adjusting the left and right side differential torque while keeping the longitudinal torque unchanged, assuming that the diameter of the left front wheel and the right front wheel is d1, and the diameter of the left rear wheel and the right rear wheel is d2, then we can get:

[0142] Front wheel torque adjustment ΔF f :

[0143] Rear wheel torque adjustment ΔF r :

[0144] Then the additional yaw torque of each wheel is as follows:

[0145] The additional yaw torque of the left front wheel is: -ΔF f *R FL ; The additional yaw torque of the right front wheel is: ΔF f *R FR ; The additional yaw torque of the left rear wheel is -ΔF r *R RL ; The additional yaw torque of the right rear wheel is ΔF r *R RR ;in,

[0146] R FL is the left front wheel radius, R FR is the radius of the right front wheel, R RL is the radius of the left rear wheel, R RR is the radius of the right rear wheel.

[0147] The additional yaw torque PID control algorithm may refer to the principle of the additional anti-slip torque PID algorithm, except that the additional yaw torque PID control algorithm and the additional anti-slip torque PID algorithm have different input values ​​and proportional coefficients.

[0148] Step S312, adjusting each of the basic torques based on the additional anti-slip torque and / or the additional yaw torque, and outputting a required torque for each of the wheels;

[0149] After the additional anti-slip torque and the additional yaw torque of each wheel are determined, each basic torque is adjusted based on the additional anti-slip torque and / or the additional yaw torque, and the required torque of each wheel is output.

[0150] In one implementation, each basic torque is adjusted based on the additional anti-slip torque and / or the additional yaw torque, and the required torque of each wheel is output, including:

[0151] For any wheel, determining a torque adjustment amount according to the additional anti-slip torque and / or the additional yaw torque;

[0152] The basic torque is adjusted according to the torque adjustment amount to obtain the required torque of the corresponding wheel; wherein,

[0153] The required torque of the wheel is the sum of the basic torque of the wheel and the torque adjustment amount.

[0154] As described above, the vehicle state may include a slipping state and an unstable state, but the vehicle may only be in a slipping state, or only be in an unstable state, or both a slipping state and an unstable state at a certain moment.

[0155] For example, if the vehicle is currently in a slipping and unstable state, take the left front wheel as an example:

[0156] Assuming that the basic torque of the left front wheel is 30 N.m, the additional anti-slip torque is -50 N.m, and the additional yaw torque is -50 N.m, the torque adjustment amount is -(50 N.m+50 N.m)=-100 N.m.

[0157] The required torque of the left front wheel is: 30-100=-70N.m.

[0158] In the same way, the required torque of all wheels can be determined.

[0159] Step S313: determining a control strategy according to the required torque of each wheel and the maximum output torque of each hub motor.

[0160] Since the maximum output torque of the hub motor is limited, it is necessary to determine the control strategy based on the required torque of each wheel and the maximum output torque of each hub motor.

[0161] In one embodiment, the required torque of each wheel and the maximum output torque of each wheel hub motor determine the driving control strategy, including:

[0162] For any wheel, if the maximum output torque of the wheel hub motor is greater than or equal to the required torque of the corresponding wheel, the control strategy is determined as follows: the wheel hub motor provides the required torque of the wheel;

[0163] If the maximum output torque of the hub motor is less than the required torque of the corresponding wheel, the control strategy is determined as: controlling the hub motor to output the maximum torque and compensating the target braking torque through the hydraulic circuit; the target braking torque is the difference between the required torque of the wheel and the maximum output torque of the hub motor.

[0164] For example, assuming that the vehicle is in a slipping and unstable state at the same time, take the left front wheel as an example:

[0165] Assuming that the basic torque of the left front wheel is 30 N.m, the additional anti-slip torque is -50 N.m, and the additional yaw torque is -50 N.m, the required torque of the left front wheel is: 30-50-50=-70 N.m.

[0166] That is, the left front wheel requires 70N.m of braking torque to prevent the vehicle from skidding and becoming unstable.

[0167] If the maximum output torque of the left front wheel hub motor is 80N.m, then the required torque of the left front wheel is provided by the hub motor.

[0168] If the maximum output torque of the wheel hub motor is less than the corresponding required torque and the vehicle is currently in a slipping state, the wheel hub motor is preferentially used to provide the maximum output torque, and the remaining insufficient torque is determined as the first remaining braking torque.

[0169] If the maximum output torque of the wheel hub motor is less than the corresponding required torque and the vehicle is currently in an unstable state, the wheel hub motor is preferentially used to provide the maximum output torque, and the remaining insufficient torque is determined as the second remaining braking torque.

[0170] If the vehicle is currently in both a slipping state and an unstable state, the CDU will determine a final target braking torque according to the first residual braking torque and / or the second residual braking torque.

[0171] It can be understood that if the vehicle is currently in a slipping state, the target braking torque is the first residual braking torque. If the vehicle is currently in an unstable state, the target braking torque is the second residual braking torque. If the vehicle is currently in a slipping state and in an unstable state at the same time, the target braking torque is the torque sum of the first residual braking torque and the second residual braking torque; and the sum of the first residual braking torque and the second residual braking torque can also be understood as the difference between the required torque and the maximum output torque of the hub motor.

[0172] Then the corresponding control strategy is: control the wheel hub motor to output the maximum torque, and compensate the target braking torque through the braking hydraulic circuit.

[0173] The brake hydraulic circuit is controlled by the IBC, that is, after the CDU determines the corresponding target braking torque, it will send a torque request to the IBC. After receiving the torque request, the IBC provides corresponding braking force to the wheels based on the target braking torque to suppress vehicle slippage and / or instability.

[0174] Continuing with the above example, assume that the vehicle is in a slipping and unstable state at the same time, and take the left front wheel as an example:

[0175] Assuming that the basic torque of the left front wheel is 30 N.m, the additional anti-slip torque is -50 N.m, and the additional yaw torque is -50 N.m, the required torque of the left front wheel is: 30-50-50=-70 N.m.

[0176] That is, the left front wheel requires 70N.m of braking torque to prevent the vehicle from skidding and becoming unstable.

[0177] If the maximum output torque of the left front wheel hub motor is -60N.m and the target braking torque is -10N.m, the CDU will send a torque request to the IBC, and the IBC will control the corresponding brake hydraulic pipeline to provide a target braking torque compensation of 10N.m.

[0178] In this way, in this embodiment, the maximum output torque provided by the distributed drive system and the braking torque provided by the chassis integrated control system can be uniformly coordinated and allocated based on the vehicle state, solving the problem of overlapping functions of the distributed drive and chassis integrated control, realizing the unified control of the distributed drive system and the chassis integrated control system, and improving the utilization rate of control resources. Moreover, when the vehicle is in an unstable state, there is no need to suppress the instability by reducing the engine torque, thereby increasing the vehicle's extreme cornering speed and improving the vehicle's handling and driving stability.

[0179] Based on the same inventive concept as the above-mentioned embodiment, this embodiment also provides a power domain chassis controller, such as Figure 4 As shown, the power domain chassis controller CDU includes:

[0180] A driving intention analysis module 21 is used to obtain the accelerator pedal opening of the vehicle;

[0181] A torque distribution module 22, used to determine the basic torque of each wheel according to the accelerator pedal opening;

[0182] A motor-driven anti-skid control module ETC, used for determining an additional anti-skid torque of the wheel;

[0183] A motor torque vector control module TVC, for determining an additional yaw torque of the vehicle;

[0184] The drive arbitration module 24 is used to adjust each of the basic torques based on the additional anti-slip torque and / or the additional yaw torque, and output the required torque of each wheel; and determine the control strategy according to the required torque of each wheel and the maximum output torque of each hub motor.

[0185] Continue to refer Figure 4, the power domain chassis controller CDU also includes: a vehicle state determination module 23, a braking drive anti-skid control module BTC, a braking stability control module VDC and a braking arbitration module 25;

[0186] Specifically, first, the VCU will monitor the fault status of various vehicle components (such as IBC, power chassis domain controller and each wheel hub motor) in real time, and determine the vehicle fault level based on the fault status.

[0187] Then, the driving intention analysis module 21 analyzes the driving intention, obtains the corresponding accelerator pedal opening, and sends the accelerator pedal opening to the torque distribution module 22 .

[0188] The torque distribution module 22 distributes torque to each wheel according to the accelerator pedal opening and the vehicle fault level, determines the basic torque of each wheel, and sends the basic torque of each wheel to the driving arbitration module 24.

[0189] Then the vehicle state determination module 23 obtains the current driving parameters of the vehicle and determines the current vehicle state according to the current driving parameters, wherein the current driving parameters may include: steering wheel angle, vehicle speed, wheel speed and other information.

[0190] The vehicle state may include a slipping state and an unstable state, but the vehicle may only be in a slipping state, or only be in an unstable state, or both slipping and instability may exist at a given moment.

[0191] Therefore, if the vehicle state determination module 23 determines that the vehicle is currently in a slipping state, the ETC module will determine the additional anti-slip torque required by the wheels and send the additional anti-slip torque to the drive arbitration module 24 .

[0192] If it is determined that the vehicle is currently in an unstable state, the TVC module will determine the additional yaw torque required by the wheels and send the additional yaw torque to the drive arbitration module 24 .

[0193] If the vehicle is currently in both a slipping state and an unstable state, the ETC module sends an additional anti-slip torque to the drive arbitration module 24 , and the TVC module also sends an additional yaw torque to the drive arbitration module 24 .

[0194] After receiving the additional anti-slip torque and / or the additional yaw torque, the drive arbitration module 24 adjusts each basic torque based on the additional anti-slip torque and / or the additional yaw torque, and outputs the required torque of each wheel; then, drive arbitration is performed according to the required torque of each wheel and the maximum output torque of each hub motor to determine the corresponding control strategy.

[0195] For example, if the maximum output torque of the hub motor is greater than or equal to the required torque of the corresponding wheel, the control strategy is: the hub motor provides the required torque of the wheel; then the drive arbitration module 24 will send the required torque of each wheel to the corresponding hub motor for execution.

[0196] For example, assuming that the vehicle is in a slipping and unstable state at the same time, take the left front wheel as an example:

[0197] Assuming that the basic torque of the left front wheel is 30 N.m, the additional anti-slip torque is -50 N.m, and the additional yaw torque is -50 N.m, the required torque of the left front wheel is: 30-50-50=-70 N.m.

[0198] That is, the left front wheel requires 70N.m of braking torque to prevent the vehicle from skidding and becoming unstable.

[0199] If the maximum output torque of the left front wheel hub motor is 80N.m, then the required torque of the left front wheel is provided by the hub motor.

[0200] However, when the maximum output torque of the hub motor is less than the corresponding required torque and the vehicle is currently in a slipping state, the hub motor is given priority to provide the maximum output torque, and the remaining insufficient torque is determined as the first residual braking torque, and the BTC module sends the first residual braking torque to the braking arbitration module 25.

[0201] If the maximum output torque of the hub motor is less than the corresponding required torque and the vehicle is currently in an unstable state, the hub motor will be given priority to provide the maximum output torque, and the remaining insufficient torque will be determined as the second residual braking torque, and the VDC module will send the second residual braking torque to the braking arbitration module 25.

[0202] If the vehicle is currently in both a slipping state and an unstable state, the BTC module will send the first residual braking torque to the brake arbitration module 25 , and the VDC module will also send the second residual braking torque to the brake arbitration module 25 .

[0203] The brake arbitration module 25 determines a final target brake torque according to the first residual brake torque and / or the second residual brake torque.

[0204] It can be understood that if the vehicle is currently in a slipping state, the target braking torque is the first residual braking torque.

[0205] If the vehicle is currently in an unstable state, the target braking torque is the second residual braking torque.

[0206] If the vehicle is currently in a slipping state and in an unstable state, the target braking torque is the sum of the first residual braking torque and the second residual braking torque. In this state, the sum of the first residual braking torque and the second residual braking torque can also be understood as the difference between the required torque and the maximum output torque of the hub motor.

[0207] Then the corresponding control strategy is: control the wheel hub motor to output the maximum torque, and compensate the target braking torque through the braking hydraulic circuit.

[0208] The brake hydraulic circuit is controlled by the IBC, that is, after the brake arbitration module 25 determines the corresponding target braking torque, it will send a torque request to the IBC. After receiving the torque request, the IBC provides corresponding braking force to the wheels based on the target braking torque to suppress the vehicle from slipping and / or instability.

[0209] Continuing with the above example, assume that the vehicle is in a slipping and unstable state at the same time, and take the left front wheel as an example:

[0210] Assuming that the basic torque of the left front wheel is 30 N.m, the additional anti-slip torque is -50 N.m, and the additional yaw torque is -50 N.m, the required torque of the left front wheel is: 30-50-50=-70 N.m.

[0211] That is, the left front wheel requires 70N.m of braking torque to prevent the vehicle from skidding and becoming unstable.

[0212] If the maximum output torque of the hub motor of the left front wheel is -60 N.m and the target braking torque is -10 N.m, the brake arbitration module 25 will send a torque request to the IBC, and the IBC will control the corresponding brake hydraulic pipeline to provide a target braking torque compensation of 10 N.m.

[0213] Since the power chassis domain controller introduced in the embodiment of the present invention is a controller used to implement the control method of the distributed drive electric vehicle in the embodiment of the present invention, based on the method introduced in the embodiment of the present invention, the person skilled in the art can understand the specific structure and deformation of the controller, so it is not repeated here. All controllers used in the method of the embodiment of the present invention belong to the scope of protection of the present invention.

[0214] Based on the same inventive concept as the aforementioned embodiment, the present invention also provides a vehicle, which includes the above-mentioned distributed drive electric vehicle control system and power chassis domain controller. The control system and power chassis domain controller of the distributed drive electric vehicle can refer to the above-mentioned corresponding description, so they will not be repeated here.

[0215] The control method, controller, system and vehicle of the distributed drive electric vehicle provided by the present invention can bring at least the following beneficial effects:

[0216] The present invention provides a control method, controller, system and vehicle for a distributed drive electric vehicle, the method comprising: obtaining the accelerator pedal opening and the vehicle fault level of the vehicle, determining the basic torque of each wheel according to the accelerator pedal opening and the vehicle fault level; determining the additional anti-skid torque of the vehicle; determining the additional yaw torque of the vehicle; adjusting each of the basic torques based on the additional anti-skid torque and the additional yaw torque, and outputting the required torque of each wheel; determining a drive control strategy according to the required torque required for each wheel and the maximum output torque of each hub motor; in this way, when the vehicle is integrated with a distributed drive system and a traditional chassis integrated control system at the same time, after determining the required torque of each wheel, the corresponding control strategy can be determined based on the maximum output torque of each hub motor, and if the maximum output torque is insufficient, the chassis integrated control system provides compensation; thereby achieving overall coordination of the functional control of the distributed drive system and the chassis integrated control system, improving the utilization rate of the control resources of the whole vehicle, and ensuring the control effect of the whole vehicle.

[0217] It can be seen that the present invention can cover the torque requirements of the entire vehicle in all scenarios (normal driving state, slipping state and unstable state) through driver intention analysis, torque distribution, unified drive anti-skid control and unified yaw control. It solves the problem of functional overlap between distributed drive and chassis integrated control, realizes the unified control of distributed drive system and chassis unified integrated control system, and optimizes the complexity of the algorithm; it not only expands the stability boundary of vehicles equipped with distributed drive, but also when the vehicle is unstable, there is no need to suppress instability by reducing the engine torque, thereby increasing the vehicle's extreme cornering speed and improving the vehicle's handling and driving stability.

[0218] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A control method for a distributed drive electric vehicle, characterized in that: Applied in a power chassis domain controller, the method comprises: Acquire the accelerator pedal opening and the vehicle fault level of the vehicle, and determine the basic torque of each wheel according to the accelerator pedal opening and the vehicle fault level; determining an additional anti-slip torque of the wheel and / or an additional yaw torque of the vehicle; adjusting each of the basic torques based on the additional anti-slip torque and / or the additional yaw torque, and outputting a required torque for each of the wheels; Determining a control strategy according to the required torque of each wheel and the maximum output torque of each wheel hub motor; Determining the basic torque of each wheel according to the accelerator pedal opening and the vehicle fault level includes: determining a first total basic torque of the vehicle according to the accelerator pedal opening; Adjusting the first total basic torque based on the fault level to obtain a corresponding total required torque; Allocating the total required torque into a front axle basic torque and a rear axle basic torque according to a torque distribution method; The average value of the front axle basic torque is determined as the basic torque of the left front wheel and the right front wheel, and the average value of the rear axle basic torque is determined as the basic torque of the left rear wheel and the right rear wheel; wherein, Determining a first total basic torque of the vehicle according to the accelerator pedal opening includes: According to the formula Determine the total output torque; If confirmed If it is greater than or equal to 1, then it is confirmed ; If confirmed If it is less than 1, then it is confirmed = ; According to the formula Determine the final torque ; According to the formula Determine the first total base torque ;in, is the maximum torque of the first hub motor. is the maximum torque of the second wheel hub motor. is the maximum torque of the third wheel hub motor. is the maximum torque of the fourth wheel hub motor. is the maximum output torque allowed by the system, I A is the maximum output current allowed by the system, I a is the current corresponding to the peak torque of each hub motor, is the accelerator pedal opening.

2. The method according to claim 1, characterized in that The determining the additional anti-slip torque of the vehicle comprises: For any wheel, determining an actual slip rate of the wheel; Based on the PID algorithm of the additional anti-slip torque, the actual slip rate of the wheel and the ideal slip rate of the wheel are determined as input values ​​of the additional anti-slip torque PID algorithm, and a first output value is obtained accordingly; the first output value is the additional anti-slip torque.

3. The method according to claim 1, characterized in that The determining an additional yaw torque of the vehicle comprises: When it is determined that the steering wheel angle of the vehicle is not 0, acquiring an actual yaw angular velocity of the vehicle; Determining an angular velocity difference between the actual yaw velocity and the ideal yaw velocity; Based on the PID control algorithm of the additional yaw torque, the angular velocity difference is used as an input value of the additional yaw torque PID control algorithm, and a second output value is obtained accordingly; the second output value is the additional yaw torque of the vehicle.

4. The method according to claim 1, characterized in that The adjusting each of the basic torques based on the additional anti-slip torque and / or the additional yaw torque and outputting a required torque of each of the wheels includes: For any wheel, determining a torque adjustment amount according to the additional anti-slip torque and / or the additional yaw torque; The basic torque is adjusted according to the torque adjustment amount to obtain the required torque of the corresponding wheel; wherein, The required torque of the wheel is a torque sum of a basic torque required by the wheel and the torque adjustment amount.

5. The method according to claim 1, characterized in that The driving control strategy is determined according to the required torque of each wheel and the maximum output torque of each wheel hub motor, including: For any wheel, if the maximum output torque of the hub motor is greater than or equal to the required torque of the corresponding wheel, the control strategy is determined as: the hub motor provides the required torque of the wheel.

6. The method according to claim 1, characterized in that The driving control strategy is determined according to the required torque of each wheel and the maximum output torque of each wheel hub motor, including: If the maximum output torque of the hub motor is less than the required torque of the corresponding wheel, the control strategy is determined as: controlling the hub motor to output the maximum torque and compensating the target braking torque through the hydraulic circuit; the target braking torque is the difference between the required torque of the wheel and the maximum output torque of the hub motor.

7. A power chassis domain controller, characterized in that: The power chassis domain controller includes: Driving intention analysis module, used to obtain the vehicle's accelerator pedal opening; A torque distribution module, used to determine the basic torque of each wheel according to the accelerator pedal opening and the vehicle fault level; the vehicle fault level is obtained from the vehicle controller VCU; a motor driven anti-skid control module, for determining an additional anti-skid torque for the wheel; a motor torque vectoring control module for determining an additional yaw torque of the vehicle; A drive arbitration module is used to adjust each of the basic torques based on the additional anti-slip torque and / or the additional yaw torque, and output the required torque of each wheel; determine the control strategy according to the required torque of each wheel and the maximum output torque of each hub motor; wherein, Determining the basic torque of each wheel according to the accelerator pedal opening and the vehicle fault level includes: determining a first total basic torque of the vehicle according to the accelerator pedal opening; Adjusting the first total basic torque based on the fault level to obtain a corresponding total required torque; Allocating the total required torque into a front axle basic torque and a rear axle basic torque according to a torque distribution method; Determine the average value of the front axle basic torque as the basic torque of the left front wheel and the right front wheel, and determine the average value of the rear axle basic torque as the basic torque of the left rear wheel and the right rear wheel; Determining a first total basic torque of the vehicle according to the accelerator pedal opening includes: According to the formula Determine the total output torque; If confirmed If it is greater than or equal to 1, then it is confirmed ; If confirmed If it is less than 1, then it is confirmed = ; According to the formula Determine the final torque ; According to the formula Determine the first total base torque ;in, is the maximum torque of the first hub motor. is the maximum torque of the second wheel hub motor. is the maximum torque of the third wheel hub motor. is the maximum torque of the fourth wheel hub motor. is the maximum output torque allowed by the system, I A is the maximum output current allowed by the system, I a is the current corresponding to the peak torque of each hub motor, is the accelerator pedal opening.

8. A control system for a distributed drive electric vehicle, characterized in that: The system comprises: The vehicle controller VCU is used to obtain the vehicle fault level; The power chassis domain controller according to claim 7, configured to receive the fault level sent by the VCU, and determine the basic torque of each wheel based on the accelerator pedal opening of the vehicle and the vehicle fault level; Determine the additional anti-slip torque of the wheel and / or the additional yaw torque of the vehicle; adjust each of the basic torques based on the additional anti-slip torque and / or the additional yaw torque, and output the required torque of each wheel; determine the control strategy according to the required torque required by each wheel and the maximum output torque of each hub motor.

9. A vehicle, characterized in that: The vehicle includes the control system of the distributed drive electric vehicle as described in claim 8.

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